Simplify & refactor Vector2

[MaxGraey]

Better avoid aggregated TypedArrays inside Math primitives like Vector2, Matrix, Quaternion and etc. In AS much more efficiently when you have less indirections. Also TypedArrays required bounds checks which also not efficient. So as example I refactored and simplify Vector2 class. It is better to refactor all other primitives in Math using the same example

[mrchantey]

This is great, I hadn't considered the cost of abstraction. I'll have a play with how this can work with linear data layouts, and then come back to the PR.